Bleed valve outlet flow deflector

ABSTRACT

A bleed valve assembly for discharging bleed air into a gas turbine engine bypass plenum includes a bleed flow duct, a bleed valve, and a flow deflector. The bleed flow duct is contoured such that it delivers uniformly flowing bleed air to the flow deflector when the bleed valve is in the open position. The flow deflector has a plurality of openings formed therein. Each opening fluidly communicates the bleed air flow passage with the bypass plenum and is oriented at a discharge angle such that bleed air is discharged from each opening in a direction that does not have a vector component in the direction in which air is flowing in the bypass plenum.

TECHNICAL FIELD

The present invention relates to bleed valves and, more particularly, toa bleed valve flow deflector/noise attenuator that enhances the mixingof relatively high temperature bleed air with lower temperature enginebypass air.

BACKGROUND OF THE INVENTION

A particular type of gas turbine engine that may be used to poweraircraft is a turbofan gas turbine engine. A turbofan gas turbine enginemay include, for example, five major sections, a fan section, acompressor section, a combustor section, a turbine section, and anexhaust section. The fan section is positioned at the front, or “inlet”section of the engine, and includes a fan that induces air from thesurrounding environment into the engine, and accelerates a fraction ofthis air toward the compressor section. The remaining fraction of airinduced into the fan section is accelerated into and through a bypassplenum, and out the exhaust section.

The compressor section raises the pressure of the air it receives fromthe fan section to a relatively high level. In a multi-spool engine, thecompressor section may include two or more compressors. For example, ina triple spool engine, the compressor section may include a highpressure compressor, and an intermediate compressor. The compressed airfrom the compressor section then enters the combustor section, where aring of fuel nozzles injects a steady stream of fuel. The injected fuelis ignited by a burner, which significantly increases the energy of thecompressed air.

The high-energy compressed air from the combustor section then flowsinto and through the turbine section, causing rotationally mountedturbine blades to rotate and generate energy. Specifically, high-energycompressed air impinges on turbine vanes and turbine blades, causing theturbine to rotate. The air exiting the turbine section is exhausted fromthe engine via the exhaust section, and the energy remaining in thisexhaust air aids the thrust generated by the air flowing through thebypass plenum.

Many gas turbine engines, such as the above-described turbofan gasturbine engine, include one or more bleed valve assemblies. The bleedvalve assemblies are used to selectively bleed some of the compressedair from the compressor section, and most notably the high pressurecompressor, before it passes through the remaining sections of theengine. As is generally known, selectively bleeding air from acompressor, via the bleed valve assemblies, is conducted to preclude thecompressor from exceeding its surge limits. For turbofan gas turbineengines, such as the one described above, the bleed air may bedischarged into the bypass plenum.

Typically, a bleed valve assembly includes a bleed valve and a bleed airduct. When the bleed valve is open, the bleed valve duct directs bleedair flow into the bypass plenum. In most instances, the outlet ports ofthese discharge ducts may include a flow diffuser and/or noiseattenuator through which the bleed air is discharged. Although presentbleed valve assemblies and flow diffuser/noise attenuator designs aregenerally safe, robust, and reliable, these devices do suffer certaindrawbacks. For example, the bypass air in the bypass plenum is typicallyat a relatively low temperature. As such, components within the plenum,including the plenum itself, may not be designed to withstand relativelyhigh temperature air. However, the bleed air from the compressor sectionis typically at a relatively high temperature. Thus, when the bleed airis discharged into the bypass plenum, if it is not sufficiently mixedwith the relatively low temperature bypass air, the temperature ofvarious components within the bypass plenum, and/or the plenum itself,can reach undesirably high temperatures.

Hence, there is a need for a bleed valve assembly and flow deflectorthat enhances the mixing of relatively high temperature bleed air withrelatively low temperature bypass air, to thereby minimize the increasein temperature of various components within the bypass plenum. Thepresent invention addresses one or more of these needs.

SUMMARY OF THE INVENTION

In one embodiment, and by way of example only, a bleed valve assemblyfor discharging bleed air into a gas turbine engine bypass plenum havingbypass air flowing therein in a first flow direction includes a bleedflow duct, a bleed valve, and a flow deflector. The bleed flow duct hasa bleed air inlet and a bleed air outlet. The bleed air inlet is adaptedto receive bleed air from a turbine engine compressor, and the bleed airoutlet is configured to discharge the bleed air into the bypass plenum.The bleed valve is disposed at least partially within the bleed flowduct and is movable between at least a closed position, in which thebleed air does not flow through the bleed flow duct, and an openposition, in which the bleed air flows through the bleed flow duct. Theflow deflector is disposed adjacent the bleed air outlet, and has aplurality of openings formed therein. Each opening fluidly communicatesthe bleed air flow passage with the bypass plenum and is oriented at adischarge angle such that bleed air is discharged from each opening in adirection that does not have a vector component in the first flowdirection.

In a further exemplary embodiment, a flow deflector for use indischarging a first gas into a passage through which a second gas flowsin a flow direction, includes a dome section and a plurality ofopenings. The dome section has a first side and a second side that isconfigured to be disposed within the passage. The plurality of openingsextend between the first and second sides. Each opening includes aninlet port and an outlet port, and is symmetrically disposed about acentral axis. Each opening is further disposed at a discharge anglerelative to a first plane that is tangent to the outlet port of theopening and intersects the central axis of the opening.

In still another exemplary embodiment, a method of making a bleed valveflow deflector includes forming a plurality of openings, each at adischarge angle, through a central section of a substantially flat platethat has a first major surface and a second major surface. At least thesection of the flat plate that includes the openings is then formed intoa substantially concave dome. The discharge angle of each opening is anacute angle relative to a line that is normal to each major surface ofthe plate.

Other independent features and advantages of the bleed valve outlet flowdeflector will become apparent from the following detailed description,taken in conjunction with the accompanying drawings which illustrate, byway of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified cross section view of a multi-spool turbofan gasturbine jet engine;

FIGS. 2 and 3 are cross section views of an embodiment of a bleed valveassembly that may be used in the engine of FIG. 1, and depicted in theclosed position and the open position, respectively;

FIGS. 4 and 5 are a cross section view and a perspective cross sectionview, respectively, of a particular embodiment of a flow deflector thatmay be used in the bleed valve assembly shown in FIGS. 2 and 3;

FIG. 6 is a top view of a substantially flat plate that may be used tomanufacture the flow deflector shown in FIGS. 3 and 4;

FIG. 7 is a close-up cross section view of a portion of plate shown inFIG. 6, depicting the configuration of the openings that are formed inthe plate; and

FIG. 8 is a simplified cross section view of a bypass plenum of a gasturbine engine, depicting an embodiment of a bleed air flow deflectorinstalled therein and with the thrust reverser blocker doors in adeployed position.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The following detailed description of the invention is merely exemplaryin nature and is not intended to limit the invention or the applicationand uses of the invention. Furthermore, there is no intention to bebound by any theory presented in the preceding background of theinvention or the following detailed description of the invention.Reference will now be made in detail to exemplary embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

An exemplary embodiment of a multi-spool turbofan gas turbine jet engine100 is depicted in FIG. 1, and includes an intake section 102, acompressor section 104, a combustion section 106, a turbine section 108,and an exhaust section 110. The intake section 102 includes a fan 112,which is mounted in a fan case 114. The fan 112 draws air into theintake section 102 and accelerates it. A fraction of the accelerated airexhausted from the fan 112 flows, in a flow direction, referred toherein as a bypass air flow direction 115, through a bypass plenum 116disposed between the fan case 114 and an engine cowl 118, and provides aforward thrust. The remaining fraction of air exhausted from the fan 112is directed into the compressor section 104.

The compressor section 104 includes two compressors, a low pressurecompressor 120, and a high pressure compressor 122. The low pressurecompressor 120 raises the pressure of the air directed into it from thefan 112, and directs the compressed air into the high pressurecompressor 122. The high pressure compressor 122 compresses the airstill further, and directs the high pressure air into the combustionsection 106. In the combustion section 106, which includes a combustor124, the high pressure air is mixed with fuel and combusted. Thecombusted air is then directed into the turbine section 108.

The turbine section 108 includes three turbines disposed in axial flowseries, a high pressure turbine 126, an intermediate pressure turbine128, and a low pressure turbine 130. The combusted air from thecombustion section 106 expands through each turbine, causing it torotate. The air is then exhausted through a propulsion nozzle 132disposed in the exhaust section 110, providing addition forward thrust.As the turbines rotate, each drives equipment in the engine 100 viaconcentrically disposed shafts or spools. Specifically, the highpressure turbine 126 drives the high pressure compressor 122 via a highpressure spool 134, the intermediate pressure turbine 128 drives the lowpressure compressor 120 via an intermediate pressure spool 136, and thelow pressure turbine 130 drives the fan 112 via a low pressure spool138.

As is shown schematically in FIG. 1, a portion of the compressed airfrom the high pressure compressor may be selectively directed into thebypass plenum 116. To do so, one or more bleed valve assemblies 200 aredisposed between the high pressure compressor 122 and the bypass plenum116. A cross section view of an exemplary bleed valve assembly 200 thatincludes a preferred flow deflector is illustrated in FIGS. 2 and 3, andwith reference thereto will now be described in more detail.

The bleed valve assembly 200 includes a bleed flow duct 202, a bleedvalve 204, and a flow deflector 206. The bleed flow duct 202 includes ableed air inlet 208, a bleed air outlet 212, and an inner surface 214that defines a bleed air flow passage 216 between the bleed air inlet208 and bleed air outlet 212. The bleed air inlet 208 is coupled to ableed air flow passage (not illustrated) that receives relatively hotbleed air from the high pressure compressor 122, and the bleed airoutlet 212 is coupled to the engine cowl 118. In the depictedembodiment, the bleed flow duct 202 is contoured such that bleed air isintroduced into the flow deflector in a substantially uniform manner.

The bleed valve 204, at least in the depicted embodiment, is mountedwithin the bleed flow duct 202 and is movable between a closed position,which is the position shown in FIG. 2, and an open position, which isthe position shown in FIG. 3. In the closed position, bleed air at thebleed air inlet 208 does not flow through the bleed air flow passage 216to the bleed air outlet 212. Conversely, and as shown more clearly inFIG. 3, when the bleed valve 204 is in the open position, bleed air atthe bleed air inlet 208 flows into and through the bleed air flowpassage 216, through the bleed air outlet 212, and into the bypassplenum 116 via the flow deflector 206. It will be appreciated that thelocation of the bleed valve 204 depicted in FIGS. 2 and 3 is merelyexemplary, and that the bleed valve may be mounted in any one ofnumerous locations within, or outside of, the bleed flow duct 202.Moreover, the bleed valve 204 may be implemented as any one of numeroustypes of valves and not just the particular physical implementation thatis depicted in FIGS. 2 and 3.

The flow deflector 206 is disposed adjacent the bleed air outlet 212,such that bleed air that is discharged from the bleed flow duct 202flows through the flow deflector 206. Although the specific physicallocation may vary, in a preferred embodiment the flow deflector 206 ismounted on the bleed air outlet 212 and, when mounted within the gasturbine engine, protrudes into the bypass plenum 116. To facilitate flowthrough the flow deflector 206, a plurality of openings 218 are formedin, and extend through the flow deflector 206. Moreover, as shown insimplified form in FIG. 3, each opening 218 is oriented at a dischargeangle such that, when the bleed valve 204 is in the open position, thebleed air, rather than being discharged unidirectionally oromnidirectionally, is discharged from each of the openings 218 in adirection that either opposes the bypass air flow direction 115, or issubstantially perpendicular to the bypass air flow direction 115.

Turning now to FIGS. 4 and 5, a cross section view and a perspectivecross section view, respectively, of a particular embodiment of the flowdeflector 206 is shown and will be described in more detail. As shown inFIGS. 4 and 5, the flow deflector 206 preferably includes a rim section402 and a dome section 404. The rim section 402 extends from the domesection 404 and is used to couple the flow deflector 206 to the bleedflow duct 202. Thus, the rim section 402 is preferably shapedsubstantially similar to that of the bleed flow duct 202, especiallynear the bleed air outlet 212. For example, in the depicted embodiment,in which the bleed flow duct 202 is substantially circular in crosssection near the bleed air outlet 212, the rim section 402 issubstantially circular in shape. It will be appreciated that the rimsection 402 may be coupled to the bleed flow duct 202 using any one ofnumerous techniques such as, for example, fasteners, brazing, orwelding. In the preferred embodiment, the rim section 402 is coupledusing a welding process.

The plurality of openings 218 are formed in, and extend between an innerside 406 and an outer side 408 of, the dome section 404. The openings218 each include an inlet port 412 that is coextensive with the innerside 406, and an outlet port 414 that is coextensive with the outer side408, to provide fluid communication between the inner and outer sides406, 408. Thus, as described above, when the flow deflector 206 iscoupled to the bleed flow duct 202, the openings 218 facilitate bleedair flow through the flow deflector 206. It will be appreciated that theshape, configuration, number, and size of the openings 218 may vary. Ina preferred embodiment, however, each opening 218 is substantiallycylindrical in shape, and are thus each symmetrically disposed about acentral axis 416. Moreover, the openings 218 preferably are equallyspaced to substantially cover the entire domed section 404, and thenumber and size of openings 218 are selected to provide a sufficientamount of flow area through the dome section 404 so as to not adverselyrestrict bleed air flow through the flow deflector 206. Although thepercent flow area through the dome section 404 may vary between, forexample, approximately 20% and approximately 45%, in a particularpreferred embodiment the percent flow area is approximately 32%.

In addition to variations in shape, configuration, number, and size, thedischarge angle and orientation of each opening 218 may also vary toprovide the above-noted relative discharge direction. For example, eachopening 218 may be formed at the same or different discharge angles, theopenings 218 located along different planes may be formed at differentdischarge angles, or openings located at different radii from the centerof the dome section 404 may be formed at different discharge angles.Preferably, however, each opening 218 is formed at the same dischargeangle (α) relative to a first plane 418 that is tangent to the outletport 414 and intersects the central axis 416 of the opening 218. It willthus be appreciated that, due to the curvature of the dome section 404,the openings 218 at different positions on the dome section 404,relative to the bypass air flow direction 115, are oriented differently.As a result, the direction in which bleed air is discharged from theopenings 218 into the bypass plenum 116 also varies. More specifically,and as shown most clearly in FIG. 4, bleed air discharged from openings218 located at relatively upstream positions is discharged in adirection that opposes bypass air flow more so than bleed air that isdischarged from openings 218 located at relatively downstream position.

It will additionally be appreciated that the specific discharge angle(α) may vary depending, for example, on the radius of curvature (R) ofthe dome section 404. However, the discharge angle (α) is selected toensure that each opening 218, whether located at a relatively upstreamor downstream position, discharges bleed air in a direction that doesnot have a vector component in the bypass air flow direction 115. In aparticular preferred embodiment, in which the dome section 404 is formedwith a radius of curvature (R) of about 5.8 inches, a discharge angle(α) of about 60° provides this preferred configuration.

It will be appreciated that the flow deflector 206 may be formed usingany one of numerous techniques and any one of numerous processes. Withreference now to FIGS. 6 and 7, a particular preferred process forforming the flow deflector 206 will be described. Referring first toFIG. 6, the flow deflector 206 is preferably formed from a substantiallyflat, circular plate constructed of a suitable material, and having asuitable diameter and suitable thickness. In a particular preferredembodiment, the plate 602 is constructed of a metal such as, forexample, nickel alloy, and has a diameter of about 8 inches, and athickness of about 0.062 inches. The plurality of openings 218 are thenformed through the plate 602 via a suitable process such as, forexample, a drilling process. As noted above, the number and size ofopenings 218 that are formed through the plate 602 may vary to provide asuitable amount of flow area. In the embodiment depicted in FIG. 6 anddescribed herein, about 2205 evenly spaced openings 218, each having adiameter of about 0.085±0.003 inches, are formed through the plate 602to provide the desired amount of flow area.

The openings 218 are each formed through the plate 602 at the samenon-perpendicular angle. In particular, and with reference now to FIG.7, it is seen that each opening 218 is preferably formed at apredetermined angle (β) relative to a line 702 that is normal to eachmajor surface 704, 706 of the plate 602. This angle may vary, but in thedepicted embodiment the predetermined angle (β) is about 30° relative tothe normal line 702. As FIG. 7 additionally depicts, a predeterminedangle (β) of 30° relative to the normal line 702, corresponds to theabove-described discharge angle (α) of 60° relative to the first plane418.

After each of the openings 218 have been formed through the plate 602,the plate 602 is then formed into a three dimensional contour thatincludes the rim section 402 and the dome section 404. It will beappreciated that the dome section 404 may be spherical, a rotation of anellipse, or any one of numerous other curved shapes. Preferably, thedome section 404 is substantially spherical and is formed by pressingthe flat plate 602 over a form having the desired curvature. It will beappreciated that when the flat plate 602 is pressed over the appropriateform to form the dome section 404, the openings 218 that were formed inthe flat plate 602 will undergo a slight realignment. However, thedischarge angle (α) of each opening remains the same. The rim section402, which is disposed around the outer periphery of the dome section404, may be formed at the same time, or after, the dome section 404 isformed.

After the flow deflector 206 is formed, it is coupled to the bleed flowduct 202 and the bleed valve assembly 200 may then be installed in theengine 100. In doing so, the bleed valve assembly 200 is preferablyinstalled in the configuration depicted in FIGS. 2 and 3, so that whenbleed air is discharged from the valve assembly 200, it is discharged ina direction that either opposes, or is substantially perpendicular to,the bypass air flow direction 115. In other words, none of the bleed airis discharged from the bleed valve assembly 200 in a direction having avector component that is in the same direction as the bypass air flowdirection 115.

Because the bleed air is discharged from the flow deflector 206 in adirection that either opposes, or is substantially perpendicular to, thebypass air flow direction 115, mixing of the relatively hot bleed airwith the relatively cool bypass air is enhanced. This enhanced mixingensures that the bypass plenum 116 and various components disposedwithin the bypass plenum 116 are exposed to relatively cooler air. Forexample, and with reference now to FIG. 8, in some aircraft engines,when the aircraft thrust reversers are deployed, a plurality of blockerdoors 802 (only one shown) are rotated into the bypass plenum 116. Inthis position, the blocker doors 502 redirect the bypass air flow in aforward direction through, for example, a plurality of non-illustratedcascade vanes, creating a reverse thrust. In such engines, the enhancedmixing of the relatively hot bleed air with the relatively cool bypassair reduces the temperatures to which the blocker doors 802 are exposedwhen the aircraft thrust reversers are deployed.

While the invention has been described with reference to a preferredembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims.

1. A bleed valve assembly for discharging bleed air into a gas turbineengine bypass plenum having bypass air flowing there-through in a firstflow direction, the valve assembly comprising: a bleed flow duct havingbleed air inlet and a bleed air outlet, the bleed air inlet adapted toreceive bleed air from a turbine engine compressor, the bleed air outletconfigured to discharge the bleed air into the bypass plenum; a bleedvalve disposed at least partially within the bleed flow duct and movablebetween at least a closed position, in which the bleed air does not flowthrough the bleed flow duct, and an open position, in which the bleedair flows through the bleed flow duct; and a flow deflector disposedadjacent the bleed air outlet, the flow deflector having a plurality ofopenings formed therein, each opening fluidly communicating the bleedair flow passage with the bypass plenum and oriented at a dischargeangle such that bleed air is discharged from each opening in a directionthat does not have a vector component in the first flow direction. 2.The assembly of claim 1, wherein: each opening includes an inlet portand an outlet port, and is symmetrically disposed about a central axis;and the discharge angle of each opening is an angle relative to a firstplane that is tangent to the outlet port of the opening and intersectsthe central axis of the opening.
 3. The assembly of claim 2, wherein thedischarge angle of each opening is an acute angle.
 4. The assembly ofclaim 2, wherein the discharge angle of each opening is between about55-degrees and about 65-degrees.
 5. The assembly of claim 2, wherein thedischarge angle of each opening is about 60-degrees.
 6. The assembly ofclaim 1, wherein the flow deflector includes: a dome section having asubstantially curved contour; and a rim section surrounding, andextending axially from, the dome section, the rim section coupled to thebleed flow duct.
 7. The assembly of claim 6, wherein the dome section issubstantially concave in orientation.
 8. The assembly of claim 1,wherein the openings are evenly spaced around the flow deflector.
 9. Theassembly of claim 1, wherein the openings are formed in a portion of theflow deflector that has a substantially spherical contour.
 10. A methodof making a bleed valve flow deflector, comprising the steps of: forminga plurality of openings, each at a discharge angle, through a centralsection of a substantially flat plate, the substantially flat platehaving a first major surface and a second major surface; and forming atleast the section of the flat plate that includes the openings into asubstantially concave dome, wherein the discharge angle of each openingis an acute angle relative to a line that is normal to each majorsurface of the plate.
 11. The method of claim 10, wherein the dischargeangle of each opening is between about 25° to about 35°.